Part of becoming a knight was earned by domesticating and training your own prowlgrin. In The Winter Knights, Quint's prowlgrin became the biggest and strongest as Quint looked after the prowlgrin very well and pampered it, nicknaming it Tash. Vilnix' prowlgrin however was neglected and mistreated which led to Vilnix' prowlgrin being taken away.

Second Age of Flight

Later, during the Second Age of Flight, Freeglade Lancers patrolled, traveled, and battled sitting astride prowlgrin mounts. The prowlgrin mounts of the Freeglade Lancers would leap across the tree canopy, jumping from branch to branch, a practice known as "tree-cresting". Wild prowlgrins also migrated across the Deepwoods in this manner.
Fenbrus Lodd had written a barkscroll about prowlgrins which Rook used to win the trust of his prowlgrin.

Third Age of Flight

Behavior and Breeding

Prowlgrin pups hatched from eggs, and grew to their full size within a few months, feeding on bits of offal. They loved Darkelm oil, and when their feet were coated in it, their tree-cresting ability increased.They communicated with a variety of squeals, barks, and whinnies, and purred when contented. They were scavengers, and wild prowlgrins often devoured the carcasses of creatures such as hammelhorns.

Known Types of Prowlgrins

There were several species or breeds of prowlgrin. The ones mentioned in the books were:

Albino

Black

Brown

Grey

Orange

Piebald

Russet

Skewbald

Striped

White

White Spotted

Different colours of prowlgrins were known to react or behave differently. For example, grey prowlgrins were known for having dependability, but not a lot of spirit, whilst orange prowlgrins were slightly smaller, but more skittish - sleek and fast, but harder to handle. Later, during the Third Age of Flight, grey prowlgrins were said to have the best jumping abilities.